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Lennox G51 Intermittent Heating

Hi Everyone,

My wife and I are new home-owners and are having some issue with our Lennox G51 furnace.

The issue I am running into is that the furnace only seems to work some of the time. It will start heating sometimes the abruptly cutoff with the status lights flashing alternately red and green. If I reset the power to the furnace sometimes it will fire up and stay lit, other times it will cycle back to Watchgaurd mode.

I took off the top panel to look through the viewport at the burners during a lighting cycle and what I see it the yellow/orange igniter flame then the blue flames will kick on for a brief second then immediately be extinguished.

After doing some reading I though it might be the condenser trap and condensation system. I drained the trap through the cleanout port and a significant amount of water came out. I also tried to remove the trap to give it a thorough cleaning but it is glued to one of the PVC pipes that it drains to so I instead flushed it a few times with clean water. I then remounted it and primed it. Alas this seems for not as the furnace is still having issues.

Where should I go from here? What more info can I provide so I can move towards a fix? My wife isn't much a fan of the cold here in Colorado at the moment.

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Thanks for the replies. I thought I was on the right side of forum rules since I wasn't looking for a step by step but more of a what direction to go now. If I was mistaken, my bad. I guess I should look for a decent Lennox tech in the Denver area, was just hoping it was something I could diagnose on my own so I don't get taken for a ride.